1. Field
The present teachings relate to a flat panel display device and a method of fabricating the same.
2. Description of the Related Art
Flat panel display devices are used as alternatives to cathode-ray tube display devices, due to their light weight and thin profile. Such flat panel display devices include liquid crystal display (LCD) devices and organic light emitting diode (OLED) display devices. Compared to the LCD devices, the OLED display devices have improved brightness, wider viewing angles, and thinner profiles, because they do not require a backlight.
OLED display devices are classified as being passive matrix or active matrix devices, according to the operating method thereof. The active matrix devices include a circuit having a thin film transistor (TFT). A TFT generally includes: a semiconductor layer having a source region, a drain region, and a channel region; a gate electrode; a source electrode; and a drain electrode. The semiconductor layer may be formed of polycrystalline silicon (poly-Si) or amorphous silicon (a-Si). However, since poly-Si has higher electron mobility than a-Si, poly-Si is used more frequently.
Generally, a flat panel display device includes: a first substrate having a display portion to display an image and a peripheral portion disposed outside the display portion; a second substrate facing the first substrate; and a sealant to attach the first substrate to the second substrate and to seal the display portion. A frit is generally used as the sealant, to prevent moisture and humidity from entering the display portion.
When the first substrate is attached to the second substrate using the frit, a signal interconnection is formed, so as to overlap with portions of the frit. The signal interconnection transmits various external signals to the display portion. Examples of the signals include an image signal for displaying a desired image, a test signal for a panel test and an aging signal for aging an organic layer. Since the adhesion between the frit and the signal interconnection is relatively weaker than the adhesion between the frit and an insulating layer, edges of the signal interconnection may become severely deformed. Thus, the surface that is attached to the frit is deformed, thereby becoming vulnerable to stress generated between the frit and the signal interconnection. As a result, the frit can be easily delaminated from the edges of the signal interconnection.